60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
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/* @(#)z_frexpf.c 1.0 98/08/13 */
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/******************************************************************
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* frexp
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*
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* Input:
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* d - floating point value
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* exp - exponent value
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*
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* Output:
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* A floating point value in the range [0.5, 1).
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*
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* Description:
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* This routine breaks a floating point value into a number f and
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* an exponent exp such that d = f * 2 ^ exp.
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*
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*****************************************************************/
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#include "fdlibm.h"
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#include "zmath.h"
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float frexpf (float d, int *exp)
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{
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float f;
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__int32_t wf, wd;
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/* Check for special values. */
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switch (numtestf (d))
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{
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case NAN:
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case INF:
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errno = EDOM;
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case 0:
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*exp = 0;
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return (d);
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}
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GET_FLOAT_WORD (wd, d);
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/* Get the exponent. */
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*exp = ((wd & 0x7f800000) >> 23) - 126;
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/* Get the mantissa. */
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wf = wd & 0x7fffff;
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wf |= 0x3f000000;
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SET_FLOAT_WORD (f, wf);
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return (f);
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}
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#ifdef _DOUBLE_IS_32BITS
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double frexp (double x, int *exp)
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{
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return (double) frexpf ((float) x, exp);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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